I have been having period like cramps that's been going on for 3 days now and i'm a week late . am i pregnant? i'm not on birth control.

Maybe. Maybe not.: Pregnancy is a common cause of a missed period. If not pregnant, other causes of a late or missed period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (especially birth control pills), hormonal disorders, etc… A home pregnancy test done at this time should give a reliable result, since one's period is one week late.